Where does MySQL store user names and passwords?

I have forgotten the administrator email and password. I want to log in to MySQL and find the database table where this is stored. Can someone tell me what it's called?

Reason: During installation, I entered the admin email and password I wanted. After successful installation, I tried to log in to the CMS but got the message that the email address and password are not correct. I tried to reinstall a number of times. Same result.

SS is pointed at a MySQL server where I had already previously installed SS. My thought was, maybe the new email/password wasn't accepted and it's looking for the old ones. So, I changed the Mysite details in the _config.php files to point at another MySQL server where I definitely knew the details. And it worked. So, if I can find the database table, it should work, no?